SectorC is a minimal C compiler written in x86-16 assembly that fits entirely within the 512-byte boot sector of an x86 machine. It supports a functional subset of C—including global variables, functions, if/while statements, and pointer dereferencing—by leveraging “Barely C,” a dialect where tokens are space-delimited to simplify lexing. By treating the standard atoi() function as a hash for keywords and identifiers, the compiler bypasses the need for complex symbol tables, allowing it to generate machine code for hardware-interactive tasks like VGA animations and PC speaker control in a remarkably small footprint.